Process and apparatus for drafting uniform roving



Feb. 20, 1951 J'. N. HIENSCH 2,542,331

PROCESS AND APPARATUS FOR DRAFTING UNIFORH ROVING Filed March 19, 1947Patented Feb. 20, 1951 PROCESS AND APPARATUS FOR DRAFTING UNIFORM ROVINGJohannes N. Hiensch, Tarrytown, N. Y.

Application March 19, 1917, Serial No. 735,737 In the Netherlands July25, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires July25, 1964 Claims. (Cl. 19--70) This invention relates to textilemachinery and processes and in particular to roving machines andprocesses.

One object of this invention is to provide a process and apparatus fordrafting or stretching a textile strand with a tension which iscontrolled automatically by the number of fibers in the cross section ofthe strand at a particular location.

Another object is to provide a process and apparatus for stretching astrand of roving wherein the electrical resistance set up in a selectedportion of the strand automatically controls the amount of tensionimparted to the strand, the strand havin been previously renderedtemporarily current-conducting, for example, by having been immersed inan electrolyte, or by having been treated with a colloidal solution ofgraphite or metal or with other finely divided conducting material.

Another object is to provide a process and apparatus, as set forth inthe preceding objects, wherein the strand of roving is stretched betweentwo spaced sets of toothed feeding and stretching rollers driven byseparate electric motors, the forward motor being automaticallycontrolled to rotate at a slightly higher speed than the rearward motorso as to impart a tension stretching to the strand.

Another object is to provide a process and apparatus, as set forth inthe preceding objects wherein the speed of the forward motor isregulated by an electrical control device in accordance with theelectrical resistance of a portion of the strand passing between spacedcontacts whereby the strand is stretched or tensioned in accordance withthe thickness of the portion passing between the contacts.

Other objects and advantages of the invention will become apparentduring the course of the following description of the accompanyingdrawings, wherein the figure shows diagrammatically one form ofelectrically controlled apparatus for automatically stretching ortensioning a strand of roving in accordance with its thickness,

' according to the present invention.

In the spinning of yarn, it is customary to draw out and slightly twistthe strands of wool or cotton, this operation and the strand produced byit being termed roving." In prior processes and apparatus for roving,the stretching or tensioning of the roving, known in the textile art asdrifting has been controlled in accordance with the strength of thestrand, regardless of its thickness. This has resulted in the strandbeing given a greater tension in its stronger portions than in 2 itsweaker-portions, and without relationship to its thickness. Hitherto,therefore, a strand of given strength has been stretched with the sametension regardless of whether the thickness of the strand is large orsmall.

In the process and apparatus of the present invention, the strand ofroving is stretched or tensioned in accordance with the number of fiberswhich are present in a given portion of the strand regardless of thestrength of the strand as a whole, or of the distribution of the fibers.In the present invention, the strand is rendered current-conducting bybeing immersed in an electrolyte or by being treated with a colloidalsolution of graphite or metal or with other finely divided conductingmaterial. An electric current is then passed through a portion of thestrand which is being conducted through spaced stretching or tensioninrollers which are electro-mechanically operated, the stretching ortensioning being controlled by the electrical resistance encountered bythe current. Thus, the amount of current which passes through theselected portion of the strand depends directly upon the number offibers in the strand. If the number of fibers is large, so that thestrand is strong, a stronger current passes through them and the strandis therefore stretched or tensioned more powerfully than when the numberof fibers is small so that the strand is weak, the electrical resistancehigher and the current weaker. I

Referring to the drawing in detail, the figure shows a preferred form ofapparatus for automatically stretching or tensioning a strand I ll ofroving composed of individual fibers II. The showing of the individualfibers l l, is of course fanciful and purely by way of illustrationsince in practice the fibers would be in discontinuous lengths and farmore closely packed so as to be individually indistingushable on thescale shown in the drawing. The strand I0 is first made temporarilyelectrically conducting by being immersed in a tank I2 containing anelectrolyte I 3 or a colloidal solution of graphite or metal or havingother means for applying fine particles of conducting material to thefibers II. The finely divided conducting material may be applied to thefibers while in solution, the fibers then being dried. The finelydivided conducting material may also be applied to the fibers in dryform. Since the current conductivity depends upon the condition ofdampness of the fibers, it

is desirable to operate the machinery and. carry out the process in aroom which is kept at a Furthermore, in order 3 constant humidity inorder to obtain a constant strength of stran In order to eliminate shortfibers or fibers lying crosswise in the strand, it is preferable to combthe strand prior to carrying out the process of the present invention.In this way, strands of maximum uniformity are obtained, the strand canbe well spread out in breadth and the stretching process can be verysensitively controlled. to minimize the breaking of the fibers in thestrand, it is advisable to separate the forward and rearward rollers25-23 and l4l5 by a distance greater than the lengths of the fibers. Theinvention results in the obtaining of a product which is very uniformand which is adapted to be readily usable for fine spinning. Thet'me-consuming doubling and trimming and repeated stretching of priorprocesses and apparatus is found to be unnecessary in practising thepresent invention.

The strand in after emerging from the tank 12 passes between grooved orroughened rearward feeding rollers l4 and I5 mounted on shafts l6 andi1. The shaft It carries a pulley l3 driven by a belt l3 from a pulleyon the output shaft 2| of an electric motor 22. The latter is providedwith electric current from the power lines 23 and 24. The shaft l1carrying the feed roller 15 may rotate freely but is preferably drivenin synchronism with the shaft IE but in the opposite direction so thatthe strand I3 is fed smoothly and evenly out of the tank I2. The shaft11, for example, may be driven by gearing (not shown) from the shaft It.In lieu of the belt I3 and pulleys i8 and 23, a s rocket chain andsprockets may obviously be substituted.

Theforward end of the strand l3 passes between forward feeding rollers25 and 25 mounted on shafts 21 and 23 respectively. The shaft 21 isdriven in a similar manner to the shaft l3 in any suitable way, such asby a pulley 23 and a belt from a pulley 3| on the output shaft 32 of anelectric motor 33. The feeding roller 25 and shaft 23, as in the case ofthe feeding roller l5 and shaft 11, may rotate freely or may bepositively driven in synchronism with the roller 25 and shaft 21, but inthe opposite direction. As stated above, this may be accomplished bysuitable gearing (not shown) arranged between the shafts 21 and 23.

In order to provide for a stretching or tensionng of the strand Hi, theforward feeding rollers 25 and 23 are driven at a slightly higher speedby the motor 33 than the rearward feeding rollers 14 and I5 by the motor22. According to the present invention, the speed of the motor 33 isregulated according to the number of fibers ll momentarily present in agiven location, such as the location between a pair of contact rollers34 and 35 located on opposite sides of the strand in between the forwardfeeding rollers 25 and 25 and the rearward feeding rollers I4 and I5.The contact rollers 34 and 35 are mounted on shafts 35 and 31respectively.

a The upper contact roller 34 is engaged by a contact arm 33 which isconnected as at 33 to a weight 43 or an equivalent spring (not shown)whereby the arm 38 is held in good electrical contact with the contactroller 34 and the latter in turn is urged downward to compress thefibers H forming the strand llil Connected to the weight 40, as by theconductor 4| is a resistance-responsive motor controller 42 of aconven-. tional type with the details of which the present invention isnot concerned. The motor controller 42 is in turn connected by aconductor 43 to a contact arm 44 engaging the shaft 21 so that when themotor controller 42 is energized, a current may flow through a circuitindicated by the arrows, a part of which circuit is formed by theportion of the strand In which, at the moment, lies between the contactrollers 34 and 35 and the forward feeding rollers 25 and 23. In order toaccomplish this, as previously stated, the strand II) has been renderedtemporarily electrically conducting by the liquid l3 in the tank l2.

The motor controller 42 is connected to the motor 33 which it controlsby the conductors 45 and 45, and is energized from the power lines 41and 43. The current supplied to the motor 33 through the conductors 45and 43 from the power lines 41 and 43 is regulated by the motorcontroller 42 in proportion to the control current flowing through thecircuit including the conductor 4|, weight 43, contact arm 33, contactroller 34, strand l3, feeding roller 25, shaft 21, contact arm 44 andconductors 43. This control current, in turn, depends on the electricalresistance of the portion 43 of the strand l0 lying between the contactrollers 34 and 35 and the'feeding rollers 25 and 23. The electricalresistance of the strand portion 43 moreover is dependent upon thenumber of fibers of which it is momentarily composed, the resistance ofcourse being higher with a small number of fibers and lower with a largenumber of fibers.

In the operation of the invention, the strand in of roving is firstimmersed in the electrolyte 13 or other conduction-producing liquid andis then threaded between the rearward feeding rollers 14 and I5, thecontact rollers 34 and 35 and the forward feeding rollers 25 and 25. Themotors 22 and 33 are then started in operation by energizing the V Themotor 22 and accordingly the feeding rollers l4 and I5 are caused torotate at a substantially constant speed, causing the strand in to befed forward at a substantially constant speed.

The motor 33, however, is caused to rotate at a much higher speed thanthe motor 22, so that the forward feeding rollers 25 and 25, by rotatingmuch more rapidly than the rearward feeding rollers l4 and I5, impart astretching or tensioning to the strand Ill. The motor 33 is caused torotate at a variable speed under the control of the motor controller 42,in accordance with the resistance encountered by the control currentpassing through the above-described control circuit, including thestrand portion 43. As the number of fibers in the strand portion 43momentarily decreases, its electrical resistance rises, hence thecontrol current in the control circuit falls. This causes the motorcontrol 42 to reduce the current flowing through the conductors 45 and45 to the motor 33, reducing the speed of the motor 33. when the numberof fibers in the strand portion 43 momentarily increases, however, theresistance of the strand portion 43 decreases, whereupon the currentfiowing in the control circuit increases, causing the motor controller42 to supplv a greater amount of current to the conductors 45 and 45 soas to cause the speed of the motor 33 to increase.

Thus, according to the invention, the strand 10 is given a greaterstretching or tension when the number of fibers in the strand portion 43momentarily increases and the strand In therefore increases in tensilestrength. Conversely,

' 15 when the number of fibers in the strand portion power lines 23, 24,41 and 43.

of the speed of the motor 33, as controlled by "the motor. controller 42in accordance with the rise and fall of the resistance in the controlcircuit and particularly in the strand portion 49, automatically variesthe tension or stretching of the strand ill in accordance with thenumber of fibers in the strand portion 49 and therefore in accordancewith the tensile strength. If the number of fibers in the strand portion49 is large, that is, if the strand is strong, then the strength of thecurrent will be great and the strand will thus be stretched or tensionedmore strongly than if the number of fibers therein is relatively small.

What I claim is:

l. A process for automatically stretching a textile strand whilepreparing it for spinning, comprising rendering the strandelectrically-conducting, electro-mechanically feeding the electricallyconducting strand at spaced forward and rearward locations along thestrand, feeding the strand at said forward location at a higher speedthan at said rearward location to stretch the strand at a predeterminedtension while feeding it, passing an electric current through a portionof the strand being stretched, and varying the tension applied to saidstrand above and below said predetermined tension in accordance with thevariation in the electrical resistance of the current-carrying portionof the strand.

2. A process for automatically stretching a textile strand whilepreparin it for spinning, comprising rendering the strandelectrically-conducting, electro-mechanically feeding theelectrically-conducting strand at spaced forward and rearward locationsalong the strand, feeding the strand at said forward location at ahigher speed than at said rearward location to stretch the strand at apredetermined tension while feeding it, passing an electric currentthrough a portion of the strand being stretched, and varying the tensionapplied to said strand above and below said predetermined tension inaccordance with the increase and decrease of the electric current asgoverned by the variation in the electrical resistance of thecurrent-carrying portion of the strand.

3. A process for automatically stretching a textile strand whilepreparing it for spinning, comprising rendering the strandelectrically-conducting by applying a current-conducting substance tothe strand, electro-mechanically feeding the electrically-conductingstrand at spaced forward and rearward locations along the strand,feeding the strand at said forward location at a higher speed than atsaid rearward location to stretch the strand at a predetermined tensionwhile feeding it, passing an electric current through a portion of thestrand being stretched, and varying the tension applied to said strandabove and below said predetermined tension in accordance with thevariation in the electrical resistance of the current-carrying portionof the strand.

4. A process for automatically stretching a textile strand whilepreparing it for spinning, comprising rendering the strandelectrically-conducting by immersing the strand in a currentconductingliquid, electro-mechanically feeding the electrically-conducting strandat spaced forward and rearward locations along the strand,

feeding the strand at said forward location at a higher speed than atsaid rearward location to stretch the strand at a predeterminedtensionwhile feeding it, passing an electric current through a portion of thestrand being stretched,

" and varying the tension applied to said strand above and below saidpredetermined tension in accordance with the variation in the electricalresistance of the current-carrying portion of the strand.

5. Apparatus for automatically stretching an electrically-conductingtextile strand while preparing it for spinning and adapted to beenergized from a source of electric current, comprising a pair of spacedrotary feeding elements mounted in forward and rearward positions alongthe strand relatively to the direction of travel of the strand forfeeding and stretching the strand, an electrical driving devicedrivingly connected to said forward feeding element, an electricaldriving device drivingly connected to said rearward feeding element,spaced electrical. contact members engaging spaced portions on apredetermined length of said strand, an electric circuit connecting saidcontact members with said source of electric current for passing saidcurrent through said predetermined length of strand, and an electricalcontrol apparatus connected to said circuit and to the forward elementdriving device and responsive to the variation of the electric currentpassin through said length of strand for varying the speed of theforward element driving device within a speed range different from andhigher than the speed of the rearward element driving device.

6. Apparatus for automatically stretching an electrically-conductingtextile strand while preparing it for spinning and adapted to beenergized from a source of electric current, comprising a pair of spacedrotary feeding elements mounted in forward and rearward positions alongthe strand relatively to the direction of travel of the strand forfeeding and stretching the strand, a variable-speed electrical drivingdevice connected to the forward feeding element, a substantially-constant-speed electrical driving device connected to therearward feeding element, spaced electrical contact members engagingspaced portions on a predetermined length of said strand, an electriccircuit connecting said contact members with said source of electriccurrent for passing said current through said predetermined length ofstrand, and an electrical control apparatus connected to said circuitand to the forward element driving device and responsive to thevariation of the electric current passing through said length of strandfor varying the speed of the forward element driving device within aspeed range different from and higher than the speed of the rearwarddriving device.

7. Apparatus for automatically stretching a textile strand whilepreparing it for spinning and adapted to be energized from a source ofelectric current, comprising an electrically-conducting substanceapplicator engaging said strand for rendering said strand electricallycurrent-conducting, a pair of spaced rotary feeding elements mounted inforward and rearward positions along the strand relatively to thedirection of travel of the strand for feeding and stretching the strand,an electrical driving device drivingly connected to said forward feedingelement, an electrical driving device drivingly connected to saidrearward feeding element, spaced electrical contact members engagingspaced portions on a predetermined length of said strand, an electriccircuit connecting said contact members with said source. of electriccurrent for-passing said current through said predetermined. length vofstrand, and an electrical control apparatus connected to said circuitand to the forward element driving device and responsive to thevariation of th electric current passing through said length of 'strandfor varying the speed of the forward element driving device within aspeed range different from and higher than the speed of the rearwardelement driving device 8. Apparatus for automatically stretching atextile strand while preparing it for spinning and adapted to beenergized from a source of electric current, comprising an immersionappliance for immersing the strand in an electrically-conducting fluid,a pair of spaced rotary feeding elements mounted in forward and rearwardpositions along the strand relatively to the dirzction of travel of thestrand for feeding and stretching the strand, an electrical drivingdevice drivingly connected to said forward feeding element, anelectrical driving device drivingly connected to said rearward feedingelement, spaced electrical contact members engaging spaced portions on apredetermined length of said strand, an electric circuit connecting saidcontact members with said source of electric current for passing saidcurrent through said predet:.rmined length of strand, and an electriccontrol apparatus connected to said circuit and to the forward elementdriving device and responsive to the variation of the electric currentpassing through said length of strand for varying the speed of theforward element driving device within a speed range differentfrom andhigher than the speed of the rearward element driving device.

9. A process for treatingan electrically conductive textile strandcomprising stretching the strand under tension while feeding the same,passing an electric current through a portion of the strand beingstretched, and varying the tension applied to the strand in accordancewith variations in the electrical current flowing through the currentcarrying portion of the strand.

10. Apparatus for automatically stretching an electrically-conductingtextile strand while preparing it for-spinning and adapted to been.-ergized from a source of electric current, comprising a pair of spacedrotary feeding elements mounted in forward and rearward positions alongthe strand relatively to the direction of travel of the strand forfeeding and stretching the strand; a driving device drivlngly connectedto said forward feeding element, a driving device drivingly connected tosaid rearward feeding eiement, spaced electrical contact membersengaging spaced portions on a predetermined length of said strand, anelectric circuit connecting said contact members with said source ofelectric current for passing said current through said predeterminedlength of strand, and an electrical control apparatus connected to saidcircuit and to one of said driving devices and responsive to thevariation of the electric current passing through said length of strandfor varying the speed of said one driving device within a speed rangedifferent from and higher than the speed of the other driving device.

JOHANNES N. HIENSCH.

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